Archive

Navigation

decaffeination

A week or to ago I explained the effects that caffeine has on your brain and body. However, there are certain people who can not handle the effects of caffeine and instead drink coffee for the pure delicious taste rather than its fantastic ability to get you through your day.

But how exactly do you get the caffeine out of the coffee bean?

Prepare to science!!

The decaffeination process starts off the same way no matter which method you use, with the bean in its green, non-roasted state.

Basically this method submerges the beans in very hot water – think of a spa but for coffee – which washes off the caffeine. The beans are then put through an activated charcoal filter. This filter stops the caffeine particles from moving through but the smaller particles like the oils and flavours are free to flow. These old beans are then thrown away and this flavour rich water (green coffee extract) is used to wash away the caffeine on new beans while maintaining the flavour. This is because there is already the flavour particles in the water so the ones inside the beans have no where to go – it’s too crowded out there for them so they just to stay at home. All together this takes about 8-10 hours.

This method requires the beans to be steamed for 30 minutes which helps to open their pores (again, sounds like a lovely day at the spa). Then to remove the caffeine the beans are then rinsed with dichloromethane or ethyl acetate for around 10 hours. The solvent is then removed and the beans are steamed once again to get rid of any of the leftover solvent.

A green bean enjoying the steaming process

Some people are concerned about the use of solvent in their coffee beans – however there is only one part per million of the actual solvent used and it is also very unlikely to survive the roasting process.

In this process the C02 (carbon dioxide) works to remove the caffeine. The green beans are soaked and then subjected to high pressure C02. The gas works as a solvent (like above) and removes the larger caffeine particles while leaving the smaller molecules behind. The caffeine is later removed from the C02 through a carbon filter. The gas can then be reused. This is a cheaper way of doing things, and less risky than the solvent method.

SUPERcritical carbon dioxide

So there are the three main ways that the coffee beans can be decaffeinated. However, if you can handle it I would recommend caffeinated coffee, as there is less damage done to the flavours. Also, the decaffeination process changes the beans to a brown colour, which makes it more difficult for the roasters to know when they are done.

Hope you enjoyed learning about the decaffeination process – see on Friday for the next post!!